Updates mypy to 0.780

Author: sobolevn

docs/pages/pipeline.rst

@@ -189,9 +189,10 @@ Let's say you have to read a file contents:
   >>> read_result = managed_read(
   ...     impure_safe(lambda filename: open(filename, 'r'))('pyproject.toml'),
   ... )
-  >>> assert is_successful(read_result)  # file contents are inside `IOSuccess`
+  >>> assert is_successful(read_result)  # file content is inside `IOSuccess`
 
-And here's how we recommend to combine ``managed`` with other pipe functions:
+And here's how we recommend to combine
+``managed`` with other pipeline functions:
 
 .. code:: python
 
@@ -201,15 +202,16 @@ And here's how we recommend to combine ``managed`` with other pipe functions:
   >>> from returns.result import safe
   >>> from returns.io import IOSuccess
 
-  >>> def parse_toml(file_contents: str) -> ResultE[dict]:
-  ...     return safe(tomlkit.parse)(file_contents)
+  >>> @safe
+  ... def parse_toml(file_contents: str) -> dict:
+  ...     return tomlkit.parse(file_contents)
 
   >>> @safe
   ... def get_project_name(parsed: dict) -> str:
   ...     return parsed['tool']['poetry']['name']
 
   >>> pipeline_result = flow(
-  ...     'pyproject.toml',
+  ...     'pyproject.toml',  # filename we work with
   ...     impure_safe(lambda filename: open(filename, 'r')),
   ...     managed_read,
   ...     bind_result(parse_toml),

docs/requirements.txt

@@ -11,5 +11,5 @@ tomlkit==0.6.0
 
 # Dependencies of our project:
 typing-extensions==3.7.4.2
-mypy==0.770
+mypy==0.780
 pytest==5.4.3

poetry.lock

@@ -56,7 +56,7 @@ typing-extensions = "^3.7"
 
 
 [tool.poetry.dev-dependencies]
-mypy = "^0.770"
+mypy = "^0.780"
 wemake-python-styleguide = "^0.14"
 flake8-pytest-style = "^1.1"
 flake8-pyi = "^20.5"

pyproject.toml

@@ -68,6 +68,9 @@ class _managed(Immutable):  # noqa: N801
     We also do not break a functional abstraction for the end user.
     It is just an implementation detail.
 
+    Type inference does not work so well with ``lambda`` functions.
+    But, we do not recommend to use this function with ``lambda`` functions.
+
     """
 
     __slots__ = ('_use', '_release')